1. Calculate the force between two objects that have masses of 70 kg and 2,000 kilograms separated by a distance of 1 meter.
2. Calculate the force between two touching grapefruits each with a radius of 0.08 meters and a mass of 0.45 kilograms.
3. Calculate the force between one grapefruit as described above and Earth. Earth has a mass of 5.9742 x10^24 kg and a radius of 6.3710 x 10^6 meters. Assume the grapefruit is resting on Earth's surface.